Field of the Invention:
The invention relates to a steam turbine installation having a steam turbine whose turbine rotor is mounted in an end bearing.
A steam turbine is normally used in a power plant installation to drive a generator or in an industrial installation to drive a working machine. For this purpose, the steam turbine is fed with steam, serving as a flow medium, which expands in the steam turbine and produces work. Following its expansion the steam usually passes via an exhaust steam housing of the steam turbine into a condenser that is arranged downstream of the latter and in which the steam condenses. The flow through the exhaust steam housing may be axial or radial. The condensate is then fed as feed water to a steam generator and, following its evaporation, passes again into the steam turbine, so that a closed water/steam loop is produced.
The turbine rotor of a steam turbine of this type is normally mounted in a number of axial and/or radial bearings. One of these bearings, also referred to as the end bearing, is arranged in the interior, for example in the inner hub, of the exhaust steam housing and is used to fix that end of the shaft of the turbine rotor which is located in the exhaust steam housing. The end bearing is normally constructed as a radial bearing, that is to say as a bearing that absorbs radial forces.
Commonly assigned, copending application Ser. No. 09/009,560 (German patent application DE 196 15 011 A1) discloses a steam turbine in which a bearing housing formed of bearing shells or halves and belonging to the end bearing of the turbine rotor is directly connected to the exhaust steam housing. For this purpose, the bearing housing of the end bearing is held centrally in the exhaust steam housing via supporting arms that are arranged radially. The bearing housing of the end bearing is arranged inside that spatial area through which steam flows during the operation of the steam turbine. However, the end bearing of a steam turbine designed in this way is particularly sensitive with regard to movements or stresses of the exhaust steam housing, for example from load changes. In addition, in the case of such a design, only a limited rigidity of the end bearing can be achieved. The arrangement of the bearing housing of the end bearing within the flow of steam also requires a high outlay in the sealing of the oil chamber with respect to the spatial area through which the steam flows.